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Biomedical subjects

A Okada

Publications and source records attributed to A Okada.

At least 127 records · Page 7Linked to original sources
PubMed1999

Intestinal adaptation in pediatric patients with short-bowel syndrome.

The purpose of this study is to evaluate 12 pediatric short-bowel syndrome (SBS) patients experienced at Osaka University Hospital and its affiliated hospitals and to study the intestinal length for achieving intestinal adaptation and the metabolic characteristics. The length of the residual small intestine ranged from 0 to 75 cm with an average of 47 cm and an ileocecal valve had been resected in five cases. Total parenteral nutrition (TPN) was started immediately after operation and was gradually substituted by enteral nutrition. No patient died during the follow-up period. Eight of 12 patients could be weaned from TPN with residual intestinal length of 27 to 75 cm (mean 57 cm). Four patients with the residual intestine of 0 to 45 cm (mean 22 cm) were unable to achieve intestinal adaptation. The rate of catheter-related sepsis per 1000 catheter days was 0.63. Fatty liver was detected in two cases, but no patient developed progressive liver failure. Plasma arginine and citrulline were decreased in patients who were unable to achieve intestinal adaptation. Our nutritional support program provided excellent survival for pediatric SBS patients primarily due to the low incidence of catheter-related sepsis and no episode of severe liver disease. Patients with more than 16 cm of residual intestinal length can be expected to be weaned from TPN.

Adaptation, Physiological↗
PubMed1999

Functional ileus in neonates: Hirschsprung's disease-allied disorders versus meconium-related ileus.

Sixty-eight neonates with functional ileus were reviewed. Twelve required laparotomy; in seven, histological studies revealed decreased ganglia and ganglion cells of the myenteric plexus (MP) (Group A), and in five, MP was normal (Group B). In the remaining 56 cases, obstructive symptoms were relieved following conservative therapy (Group C). All Group A cases except one had normal birth weight, while Group B and C cases showed significantly lower birth weights. A marked caliber change of the small intestine and/or small-caliber distal intestine with meconium stagnation in the proximal intestine was commonly demonstrated at operation in Group A and B, or on contrast enema in Group C. Four Group A cases died of enteritis, and three survivors suffered from prolonged obstructive symptoms. The grade of histological abnormality of MP correlated with the clinical outcome. In Group B, three died of sepsis shortly after surgery, but two survivors have been free from symptoms. Group A can be categorized as Hirschsprung's disease-allied disorders (HAD). Group B and C can be categorized as meconium-related ileus (MRI). The similarity of the macroscopic findings of HAD and MRI, and the occurrence of MRI exclusively in low birth weight neonates, strongly suggest that functional immaturity of MP plays a role in the etiology of MRI.

Ganglia↗
PubMed1999

Nitric oxide synthase inhibitor attenuates intestinal damage induced by zinc deficiency in rats.

A nitric oxide synthase (NOS) inhibitor, NG-nitro-L -arginine methyl ester (L-NAME), was given to zinc-deficient (ZD) rats to determine whether it prevents the intestinal damage usually observed under these conditions. Weanling male rats were given free access to a ZD diet (2 mg zinc/kg), whereas control rats including pair-fed (PF) and ad libitum consumption (AL) groups were given a zinc-supplemented (50.8 mg zinc/kg) diet for 4 wk. Half of the ZD rats received L-NAME (0.3 g/L in drinking water) for 3 wk starting at the wk 2 of the deficient period. Plasma zinc concentration in ZD rats was significantly lower (P < 0.05) than that of AL and PF rats. Administration of L-NAME did not alter this concentration. Intestinal zinc concentration did not differ among groups. However, metallothionein-1 (MT-1) mRNA level was significantly lower in the intestine of ZD rats than in AL or PF rats. Treatment of ZD rats with L-NAME did not affect this level. Intestinal microvascular permeability evaluated by Evans blue showed significantly higher extravasation in ZD rats than in AL rats, whereas L-NAME administration inhibited the extravasation. Expression of inducible NOS mRNA was observed in intestine of ZD but not of AL or PF rats, and there was no significant difference between ZD rats, regardless of L-NAME treatment. The activity ratio of inducible NOS to total NOS in ZD rats not receiving L-NAME was significantly higher than that in AL rats or ZD rats treated with L-NAME (P < 0.05). The number of apoptotic-positive and goblet cells in intestinal villi was significantly higher in ZD rats compared with AL or PF rats. L-NAME administration in ZD rats reversed this effect. These results indicate that inhibition of NOS ameliorates zinc deficiency-induced intestinal damage in rats.

Animals↗
PubMed1999

Prognostic value of heart rate variability during long-term follow-up in chronic haemodialysis patients with end-stage renal disease.

BACKGROUND: Mortality is high in chronic haemodialysis patients with cardiovascular disease, and many of them die suddenly. Reduced heart rate variability (HRV) is an increased risk for death in various populations, but its prognostic value in haemodialysis patients remains uninvestigated. METHODS: We analysed the associations between 24-h HRV measures and long-term mortality through a prospective follow-up of 31 chronic haemodialysis patients who underwent diagnostic coronary angiography. RESULTS: Of the 31 patients, at baseline, seven had a previous myocardial infarction, five had a history of congestive heart failure and 14 had significant (> or =75%) coronary stenosis (four had multi-vessel stenosis). During follow-up for 60+/-5 months, 14 patients died, 11 of them suddenly. A left ventricular ejection fraction of <0.45, multi-vessel coronary stenosis, ventricular tachycardia on 24-h ECG and decreased/abnormal 24-h HRV (triangular index <22 and abnormal Poincaré plot) carried a univariate risk of all-cause death, while the risk of sudden death was only correlated with decreased HRV (standard deviation of normal-normal R-R interval <50 ms, triangular index <22 and ultra-low frequency power <8.7 ln(ms2)). Multivariate analysis revealed that a triangular index <22 was the best predictor of increased risk for both all-cause and sudden death (hazards ratio (95% CI); 8.1 (1.3-48.6) and 12.6 (1.3-126.4), respectively) and that the association was independent of cardiac function, macrovascular diseases, ventricular arrhythmias and cardiovascular risk factors. The 5-year mortality when the triangular index was > or =22 or <22 was 33 or 88% for patients with coronary artery disease and 0 or 50% for those without. CONCLUSIONS: These results indicate that HRV has an independent prognostic value in chronic haemodialysis patients and identifies an increased risk for all-cause and sudden death.

Adult↗
PubMed1999

Pancreatic CT imaging: effects of different injection rates and doses of contrast material.

PURPOSE: To assess the effects of the intravenous injection rate and dose of contrast material on pancreatic computed tomography (CT). MATERIALS AND METHODS: A total of 126 patients were divided at random into four groups with different injection rates and doses. Groups 1 and 2 underwent injection of 2 mL per kilogram of body weight of 300 mg of iodine per milliliter of contrast material, and groups 3 and 4 underwent injection of 1.5 mL/kg. The injection rate was 5 mL/sec for groups 1 and 3 and 3 mL/sec for groups 2 and 4. Single-level serial CT scanning was performed at the level of the pancreatic head, and the pancreatic enhancement value was calculated. RESULTS: The maximum pancreatic enhancement value was 99 HU +/- 18 (mean +/- SD) for group 1, 90 HU +/- 18 for group 2, 86 HU +/- 15 for group 3, and 74 HU +/- 13 for group 4. There were significant differences in the maximum pancreatic enhancement value between groups 1 and 2 (P = .045), between groups 3 and 4 (P = .001), between groups 1 and 3 (P = .016), and between groups 2 and 4 (P = .001). CONCLUSION: Both a higher dose and a faster injection rate increased the maximum pancreatic enhancement value.

Adult↗
PubMed1999

Aging and spectral characteristics of the nonharmonic component of 24-h heart rate variability.

To examine whether heart rate variability (HRV) during daily life shows power law behavior independently of age and interindividual difference in the total power, log-log scaled coarse-graining spectra of the nonharmonic component of 24-h HRV were studied in 62 healthy men (age 21-79 yr). The spectra declined with increasing frequency in all subjects, but they appeared as broken lines slightly bending downward, particularly in young subjects with a large total power. Regression of the spectrum by a broken line with a single break point revealed that the spectral exponent (beta) was greater in the region below than above the break point (1.63 +/- 0. 23 vs. 0.96 +/- 0.21, P < 0.001). The break point frequency increased with age (r = 0.51, P < 0.001) and beta correlated with age negatively below the break point (r = 0.39) and positively above the break point (r = 0.70). The contribution to interindividual difference in total power was greater from the differences in the power spectral density at frequencies closer to both ends of the frequency axis and minimal from that at -3.25 log(Hz), suggesting hingelike movement of the spectral shape at this frequency with the difference in total power. These characteristics of the 24-h HRV spectrum were simulated by an artificial signal generated by adding two noises with different beta values. Given that the power law assumption is fundamental to the analysis of dynamics through the log-log scaled spectrum, our observations are substantial for physiological and clinical studies of the heartbeat dynamic during daily life and suggest that the nonharmonic component of HRV in normal subjects during daily life may include at least two 1/fbeta fluctuations that differ in dynamics and age dependency.

Adult↗
PubMed1999

Branched-chain amino acid therapy for spinocerebellar degeneration: a pilot clinical crossover trial.

OBJECT: The potential effects of branched-chain amino acids (BCAAs) on spinocerebellar degeneration (SCD) were explored in eleven patients. METHODS: The patients received 200 ml of BCAA-rich solution, 2 mg of thyrotropin-releasing hormone (TRH; protirelin), or a placebo daily for 7 days each in a random order. An SCD score was used to quantify the severity of symptoms. PATIENTS: Eleven patients with SCD (7 male, 4 female; mean age 60+/-11; mean disease duration 5.5 years) participated in this study. RESULTS: The mean SCD score of the eleven patients improved significantly by the BCAA treatment compared with the baseline. The conditions of five of the eleven patients (45%) were clearly improved by the BCAA treatment. All of the responders manifested predominantly cerebellar symptoms, but no prominent parkinsonian symptoms. Two patients with marked rigidity and akinesia did not respond to the treatment. CONCLUSION: We concluded that BCAAs do have a beneficial effect on functional improvement in patients with SCD, and that further large scale studies are needed.

Adult↗
PubMed1999

The importance of the plasma amino acid molar ratio in patients with biliary atresia.

BACKGROUND: Plasma amino acid patterns and the therapeutic benefits of amino acid supplements are not examined well in postoperative patients with biliary atresia (BA). This study aimed to investigate profiles of the amino acid molar ratio, the Fischer molar ratio (FR, valine + leucine + isoleucine/phenylalanine + tyrosine), and relationships with other nutritional parameters and to assess the efficacy of enteral nutrient preparations for hepatic failure in patients with BA. METHODS: In study 1 profiles of FR were analyzed in 24 patients with BA (aged 3 to 12 years) in the postoperative period and compared with liver function tests and anthropometric measures. In study 2 10 patients with BA with a FR < 2.0 were begun on a dietary regimen consisting of an ordinary diet supplemented with a branched-chain amino acid-enriched elemental diet. RESULTS: Study 1: In jaundiced patients with total bilirubin levels > 2.0 mg/dL the FR remained below 2.0 throughout the period of observation, in contrast with nonjaundiced patients. The FR was closely related to the levels of serum albumin and plasma rapid turnover proteins and anthropometric measures as well as biochemical data reflecting intrinsic liver function. Study 2: A significant increase in rapid turnover proteins and improvement of general status were noted concurrently with an increase of the FR. CONCLUSIONS: The FR indicates a combination of nutritional status and intrinsic liver function in post-operative BA patients. The FR is a useful parameter in conducting nutritive therapy with a branched-chain amino acid-enriched elemental diet in those patients.

Adolescent↗
PubMed1999

Expression of NOS II and its role in experimental small bowel ulceration in rats.

BACKGROUND: Overproduction of nitric oxide (NO) has been implicated in the pathogenesis of experimental and clinical inflammatory bowel disease (IBD). METHODS: We observed the expression and localization of inducible NO synthase (NOS-II) in small intestinal ulceration induced by indomethacin in rats. The role of NO was investigated by using NO synthase inhibitors. RESULTS: The small intestine was affected by longitudinal ulcers after indomethacin administration and ulceration was associated with distinctive expression of NOS-II protein and mRNA. The amount of its expression was found to correlate with the extent of inflammation. Histologically, both immunohistochemistry and in situ hybridization revealed a similar localization of NOS-II to inflammatory and epithelial cells. The possible amelioration of the inflammation was modulated by aminoguanidine (AG) and NG-nitro-L-arginine methyl ester (L-NAME) treatment for 10 days. Both AG and L-NAME attenuated intestinal myeloperoxidase activity and gross inflammation, only AG was found to decrease intestinal permeability with a significant amelioration of body weight loss. CONCLUSION: These findings indicate that NO derived mainly from inflammatory cells may play an important role in the pathophysiology of intestinal ulceration and offer the potential for future treatment directed at blocking neutrophils recruitment and NO overproduction in IBD.

Animals↗
PubMed1999

[Roles of matrix metalloproteinases and tissue inhibitor of metalloproteinase (TIMP) in cancer invasion and metastasis].

During the progression of cancer invasion and metastasis, remodeling such as degradation of extracellular matrices (ECM) in cancer tissues and surrounding tissues is the most important event. Degradation of ECM modulates cell-cell and cell-matrix interactions, and this changes cell behavior and the cell microenvironment. This review considers the cellular and organismal function of matrix metalloproteinases, especially of membrane-type matrix metalloproteinases, and their inhibitor, tissue inhibitor of metalloproteinase (TIMP).

Humans↗
PubMed1999

Revision laparoscopy for incarcerated hernia at a 5-mm trocar site following pediatric laparoscopic surgery.

We report the case of a 6-month-old female infant who developed post-operative bowel obstruction due to an incarcerated hernia through a 5-mm laparoscopic wound. The patient underwent laparoscopic Nissen fundoplication for gastroesophageal reflux. On day 6, she showed symptoms of ileus, and the diagnosis of a trocar wound hernia was made on day 13. The herniated intestine was reduced and the defective peritoneum and fascia were closed under relaparoscopic guidance, thus avoiding full-scale laparotomy. A trocar wound hernia causing early postoperative bowel obstruction is a rare complication, especially at 5-mm trocar puncture sites. Intraoperative dislodgment and reinsertion of working trocars may create fascial defects larger than the actual size of the trocar. All laparoscopic puncture wounds, even those <10 mm in size, should be closed at the fascial level in infants. Revision laparoscopy is considered preferable to manage trocar site complications in children.

Female↗
PubMed1998

Complex demodulation of cardiorespiratory dynamics preceding vasovagal syncope.

BACKGROUND: The dynamic autonomic processes leading to vasovagal syncope are poorly understood. METHODS AND RESULTS: We used complex demodulation to continuously assess changes in respiration, R-R interval, and arterial pressure (blood pressure) variability during 60 degree head-up tilt in 25 healthy subjects with tilt-induced vasovagal syncope and 25 age-matched nonsyncopal control subjects. Coherence and transfer function analyses were used to examine the relation between respiration and R-R interval variability before syncope. Baseline blood pressure, R-R, and ventilation were similar between syncope subjects and control subjects. Syncope subjects experienced an increase in tidal volume and decrease in BP beginning 3 minutes before impending syncope (systolic blood pressure <80 mm Hg) necessitated termination of tilt. Approximately 90 seconds before syncope there was a sudden prolongation of R-R interval and increase in amplitude of high and low frequency R-R interval variability, indicating an abrupt enhancement of vagal tone. The increase in respiratory amplitude between 180 and 90 seconds before syncope was not accompanied by changes in R-R interval or R-R variability, suggesting a dissociation between respiration and the respiratory sinus arrhythmia. The coherence analysis showed fewer syncope subjects with coherence between respiratory and R-R interval variabilities and lower transfer magnitudes in syncope subjects compared with control subjects. Nonsyncopal subjects had no change in respiratory, R-R interval, or blood pressure dynamics during matched time periods before the time of syncope. CONCLUSIONS: Vasovagal syncope is preceded by a period of hyperpnea and cardiorespiratory decoupling followed by an abrupt increase in cardiovagal tone. Respiratory pumping without inspiratory cardiac slowing may partially counteract preload reduction until sudden bradycardia precipitates syncope.

Adult↗
PubMed1998

TIMP-2 promotes activation of progelatinase A by membrane-type 1 matrix metalloproteinase immobilized on agarose beads.

Membrane-type 1 matrix metalloproteinase (MT1-MMP)/MMP-14 is the activator of progelatinase A (proGelA)/proMMP-2 on the cell surface. However, it was a paradox that a tissue inhibitor of metalloproteinase-2 (TIMP-2), which is an inhibitor of MT1-MMP, is required for proGelA activation by the cells expressing MT1-MMP. In this study, a truncated MT1-MMP having a FLAG-tag sequence at the C terminus (MT1-F) was immobilized onto agarose beads (MT1-F/B) and used to analyze the role of TIMP-2. The proteolytic activity of MT1-F/B against a synthetic peptide substrate was inhibited by TIMP-2 in a dose-dependent manner. In contrast, TIMP-2 promoted the processing of proGelA by MT1-F/B at low concentrations and inhibited it at higher concentrations. TIMP-2 promoted the binding of proGelA to the MT1-F on the beads by forming a trimolecular complex, which was followed by processing of proGelA. A stimulatory effect of TIMP-2 was observed under conditions in which unoccupied MT1-F was still available. Thus, the ternary complex is thought to act as a means to concentrate the substrate to the bead surface and to present it to the neighboring free MT1-F.

Animals↗
PubMed1998

Prolonged preoperative stabilization using high-frequency oscillatory ventilation does not improve the outcome in neonates with congenital diaphragmatic hernia.

Although delayed repair with preoperative stabilization using high-frequency oscillatory ventilation (HFOV) has been advocated in neonates with congenital diaphragmatic hernia (CDH), improved survival has not been reported. We compared survival between neonates undergoing delayed repair after prolonged stabilization for more than 48 h using HFOV and those undergoing immediate repair following short stabilization using HFOV in subjects with high-risk CDH. Patient selection was made by two criteria: fetuses with the lung/thorax transverse area ratio (L/T) below 0.26 and neonates who presented with respiratory distress significant enough to require intubation within 6 h after delivery. Selection of the strategies differed by era and medical center. Stabilization failed in 11 of 18 patients with delayed repair and only 7 patients (38.9%) in this group survived, but 18 of 23 patients (78.3%) in the immediate-repair group survived (P < 0.05). Although lower values of Apgar scores, best postductal PO2 (BPtDPO2), gestational weeks, and L/T and more frequent patch repair were observed in the delayed than in the immediate repair group, significant differences in survival among the subpopulations were also observed in the prenatally diagnosed group, including the group with L/T < 0.15 and the group that required ECMO, the group with the best preductal PO2 (BPrDPO2) >/= 100 torr, and the group with BPtDPO2 < 100 torr. These results indicate that prolonged stabilization for more than 48 h using HFOV does not improve survival in patients with high-risk CDH.

Combined Modality Therapy↗
PubMed1998

Pyloric motor abnormality in patients with infantile hypertrophic pyloric stenosis.

There are no published data of manometric studies of pyloric motor function in patients with infantile hypertropic pyloric stenosis (IHPS). The present study attempted to examine the characteristics of motor abnormality of the pylorus in five children with IHPS. Using a transducer-built-in manometric catheter cannulated through the pylorus under fluoroscopy, the pressure in the pyloric canal was recorded continuously over 3 h during fasting. Clusters of high-amplitude spastic contractions of over 300 mmHg were recorded at intervals. The frequency was 1-3/min (mean 1.7 cpm) and the duration was 7-15 s. These periodic spastic contractions were suppressed temporarily for 20-30 min after intravenous injection of 0.01 mg/kg atropine. After pyloromyotomy, these spastic contractions decreased remarkably in amplitude, but there were no changes in frequency. It is concluded that the underlying motor abnormality observed in hypertrophied pyloric muscle is clusters of high-amplitude contractions, although more precise measurements of basal pyloric pressure are needed to explore the pathophysiology of IHPS in detail. The effect of pyloromyotomy may be related to the decrease in high-amplitude contractions.

Atropine↗